Broadband optical network apparatus and method
Methods and apparatus for providing enhanced optical networking service and performance which are particularly advantageous in terms of low cost and use of existing infrastructure, access control techniques, and components. In the exemplary embodiment, current widespread deployment and associated low cost of Ethernet-based systems are leveraged through use of an Ethernet CSMA/CD MAC in the optical domain on a passive optical network (PON) system. Additionally, local networking services are optionally provided to the network units on the PON since each local receiver can receive signals from all other users. An improved symmetric coupler arrangement provides the foregoing functionality at low cost. The improved system architecture also allows for fiber failure protection which is readily implemented at low cost and with minimal modification.
1. A computerized method of adjusting an optical power of an optical network unit (ONU) of a passive optical network, the computerized method comprising:
accessing data descriptive of at least an expected received power level corresponding to an optical communications path between the ONU and a first optical coupler of the passive optical network;
calculating a transmitter power level of the ONU based at least on the accessed data descriptive of at least the expected received power level; and
adjusting a current transmitter power level to the calculated transmitter power level.
2. The computerized method of claim 1 , further comprising:
transmitting a self-ranging message to the first optical coupler;
receiving the self-ranging message from a second optical coupler; and
determining a round-trip distance of an optical communications path through the first optical coupler and the second optical coupler, the determining the round-trip distance comprising measuring: (i) a transmit time corresponding to the transmitting of the self-ranging message to the first optical coupler and (ii) a receipt time of the self-ranging message from the second optical coupler;
wherein the calculating of the transmitter power level of the ONU is directly proportional to the determined round-trip distance.
3. The computerized method of claim 1 , further comprising determining whether a signal power received at the ONU correlates with the expected received power level, the correlation being based at least on:
(i) a difference of values between the signal power received at the ONU and the expected received power level and (ii) a predetermined error range.
4. The computerized method of claim 3 , further comprising, when the difference of values falls outside of the predetermined error range:
readjusting, at least once, the current transmitter power level of the ONU; and
comparing a difference of values between (i) a readjusted signal power received at the ONU and (ii) the expected received power level.
5. The computerized method of claim 4 , further comprising, when the difference of values between (i) the readjusted signal power received at the ONU and (ii) the expected received power level falls outside of the predetermined error range, causing the ONU to enter a non-operational state, the non-operational state for implementing a corrective action.
6. The computerized method of claim 3 , further comprising, when the difference of values falls inside the predetermined error range, causing the ONU to enter an operational state.
7. The computerized method of claim 1 , wherein the accessing of the data further comprises accessing information descriptive of at least: (i) a distance between the ONU and the first optical coupler and (ii) the current transmitter power level of the ONU.
8. An optical network unit (ONU) comprising:
at least one optical communications interface configured to perform data communication with (i) an optical access point of a passive optical network and (ii) an optical coupler of the passive optical network;
a transmitter comprising a transmitter power associated therewith;
processor apparatus in data communication with the at least one optical communications interface; and
a non-transitory computer-readable storage apparatus in data communication with the processor apparatus and having at least one computer program, the least one computer program comprising a plurality of instructions configured to, when executed by the processor apparatus, cause the ONU to:
perform an initialization comprising: (i) transmission of a message to the optical coupler, (ii) receipt of a message from the optical coupler at the ONU, and (iii) determination of a distance to the optical coupler based at least on measurements of a time taken for the transmission to the optical coupler and a time taken for the return and receipt by the ONU;
access a data resource file comprising at least an expected power level; and
adjust the transmitter power level of the ONU based at least on the expected power level and the determined distance to the optical coupler.
9. The optical network unit of claim 8 , wherein the plurality of instructions are further configured to, when executed by the processor apparatus, cause the ONU to compare a received power level to the expected power level;
wherein the ONU is configured to, responsive to a value derived from the comparison between the received power level and the expected power level within a predetermined error, enter an operational state; and
wherein the ONU is further configured to, responsive to the value derived from the comparison between the received power level and the expected power level being outside the predetermined error, readjust the transmitter power level.
10. The optical network unit of claim 9 , wherein the ONU is further configured to, when the readjustment of the transmitter power occurs:
responsive to a value derived from a comparison between another received power level and the expected power level within the predetermined error, enter the operational state; and
responsive to the value derived from the comparison between the other received power level and the expected power level being outside the predetermined error, enter a non-operational state.
11. The optical network unit of claim 10 , wherein the entrance to the non-operational state comprises an institution of a corrective action, the corrective action comprising one or more of (i) a log of the non-operational state and/or (ii) a report of the non-operational state.
12. The optical network unit of claim 8 , wherein the ONU is configured to perform a calibration prior to power-up of the ONU, the calibration comprising:
determination of at least the expected power level, where the expected power level corresponds to an optical communications path between the ONU and the optical coupler; and
storage of information related to at least the expected power level within the data resource file.
13. The optical network unit of claim 8 , wherein the at least one optical communications interface comprises at least:
a first optical communications interface configured to receive digital data from the optical access point; and
a second optical communications interface configured to transmit digital data from the ONU.
14. The optical network unit of claim 13 , wherein the passive optical network is configured to allow redirection of the digital data transmitted from the ONU to a second ONU via a second optical coupler of the passive optical network.
15. An optical network comprising:
an optical line terminal (OLT) configured to exchange data with a switched network;
a plurality of optical couplers in data communication with the OLT; and
an optical network unit (ONU), the ONU configured to:
access data descriptive of at least an expected received power level corresponding to an optical communications pathway between the ONU and the plurality of optical couplers;
determine a transmitter power level of the ONU based at least on the data descriptive of at least the expected received power level;
adjust a current transmitter power level of the ONU based on a comparison of the current transmitter power level with the determined transmitter power level;
responsive to a comparison between the adjusted transmitter power level and the expected power level within a predetermined error, enter an operational state; and
responsive to the comparison between the adjusted transmitter power level and the expected power level outside the predetermined error, readjust the transmitter power level.
16. The optical network of claim 15 , wherein the plurality of optical couplers comprises at least a P×N star coupler.
17. The optical network of claim 15 , wherein the ONU is configured to receive one or more of: video traffic signals and/or data traffic signals.
18. The optical network of claim 17 , wherein the OLT is configured to transmit the video traffic signals and/or the data traffic signals.
19. The optical network of claim 15 , wherein the determined transmitter power level is determined from a self-ranging process, the self-ranging process comprising a transmission of a message from the ONU to itself via the plurality of optical couplers.
20. The optical network of claim 15 , wherein:
the plurality of optical couplers comprises a first and a second optical coupler;
the ONU comprises a first ONU configured to communicate data with a second ONU; and
the entrance to the operational state is configured to enable the first ONU and the second ONU to communicate data with each other via optical pathways, the optical pathways being configured to provide optical signal communication between the first and the second optical couplers.